Sunday, November 26, 2006

VW - Annealing Copper Washers

>I was thinking that a while back someone said that you can take the copper >washers and heat them with a torch till they are red hot and then let them >cool and you can reuse them. The heating returns their flexibility.


You heard wrong. On two counts.

Heating copper then flicking it into cold water is how you anneal it; make it softer.

But part of the problem is that the washers have been crushed -- their thickness has been reduced. Annealing them does not make them thicker.

The VW sump plate was secured with acorn nuts. Their purpose was to limit how far the nut can be threaded onto the stud. With undistorted parts, meaning they should be flat, and gaskets of the proper thickness and composition, meaning they should be impregnated paper rather than plain cardboard, and a copper washer of the proper thickness and temper, putting it all together and torqued to the proper spec ( 5 ft-lbs ) gave you a leak-free fit automatically.

That was then.

Over time, the acorn nuts vanished, replaced with a common nut installed with an un-specified amount of torque, which made the thickness and temper of the copper washers even more critical than before.

drip drip drip...

-Bob Hoover

No comments: